1. Field of the Invention
The invention relates to technology related to a stator used in a rotary electric machine such as an electric motor or a generator.
2. Description of Related Art
A stator has a structure in which a stator coil (hereinafter, simply referred to as a coil) is wound around a stator core. An insulating body may be arranged between the stator core and the coil to insulate them from each other. For example, molten resin may be filled around the coil to fix the position of the coil such that the coil is covered by a resin-molded product formed when the molten resin harden.
Japanese Patent Application Publication No. 2010-246269 (JP 2010-246269 A) describes technology for assembling a stator to an insulating body formed in advance. Japanese Patent Application Publication No. 2012-60795 (JP 2012-60795 A) describes technology for injection forming an insulating body around a stator core. A coil is wound along a side surface of the stator core in the circumferential direction, as well as upper and lower surfaces in the axial direction. Therefore, with both of these technologies, the insulating body is provided with a side wall that covers the side surface of the stator core in the circumferential direction, and an upper wall that covers the upper surface of the stator core in the axial direction.
When a coil is covered with a resin-molded product formed by filling molten resin around a coil wound along a circumferentially side wall and an axially upper wall of an insulating body, the molten resin flows, toward the upper surface along the circumferentially side wall of the stator core, and crosses the boundary between the circumferentially side wall and the axially upper surface, after which the molten resin fills the space above the upper wall of the insulating body and the axially upper surface of the stator core. At this time, air tends to mix in with the molten resin, so there tends to be voids (bubbles) in the resin-molded product. If there are voids in the resin-molded product, cracks tend to form from the voids, and portions of the resin-molded product tend to peel away due to the cracks. The resultant scrapings may affect the operation of the rotary electric machine.